99 TJ error codes

flyboy

New member
I have a 99 tj and it is reading an error code of 2.5 Anyone have an idea of where to start. I have read what it means but it is unclear. The only other thing it does is idles a little wierd(up and down by 200 rpm at idle) and the exhaust stinks a little.
 
25 is: A shorted or open condition detected in one or more of the idle air control motor circuits. Actual idle speed does not equal target idle speed.

The Idle Air Control (IAC) is bolted to the passenger side of the throttle body. The IAC housing is attached with 4 tamper proof torx, and the IAC motor unbolts from that. Try cleaning the IAC motor and housing with a toothbrush and carb cleaner, clean the entire throttle body while you're at it.

Reset the codes and see if that does the trick. If it doesn't, replace the IAC motor.
 

Comanche??? NE1?

hey good trick i learned in school spray the inside with carb cleaner and clean it out first then, let the car run till its warmed up, run it at a high idle around 2k rpm then quickly stuff a rag into the throttle opening, this will make your engine stall, what this does is cleans out your idle air passages of the film and gunk, the sudden loss of air comming through the throttle will suck what ever build up you have in the throttle body into the engien and expelled out the exhaust. this is exp[ecially good with carbs.
 
How are you reading an error code on a '99 TJ? My 99 always read 2.5 when I tried that code reading trick, until I discovered that 99s can't do it.
99TJ s are one of the few years that Jeep took the on board code reader out. Something to do with the sentry key option. Get yourself a cheap harbour freight code reader ($38.00) and be sure. '99TJ codes are all four digits now anyway.
 
Im overhauling my 258 and need some tips

flyboy said:
how do i reset the codes after i have cleaned it?
Disconnect the battery for about 15 minutes.

The '99 still does use the 2-digit codes and they are retrievable. If you're always read 25, it was always throwing a code.
 

Kaybone is correct, the codes from 99 on are diffrent. 25 code kept coming up on mine so I changed the IAC in mine. $80 later was still pulling the same code. After using sombody elses computer it came up that it was an ingnition problem. Is yours distributorless? That is when the change in codes happended. Some of the 99's are the old set up and some are the new style.
 

Bounty__Hunter said:
flyboy said:
how do i reset the codes after i have cleaned it?
Disconnect the battery for about 15 minutes.

The '99 still does use the 2-digit codes and they are retrievable. If you're always read 25, it was always throwing a code.

Disconnecting the battery will ONLY work on OBD-I compatible computer systems.

Any vehicle sold in the U.S. after the 1995 model year uses an OBD-II compatible computer system which CANNOT be "reset" except through an OBD-II scanner. Disconnecting the battery has no effect as the newer computers have non-violate memory. :mrgreen:

-Nick :!:
 
Now I'm all screwed up, Bounty has always came through for me, but with so many debating the error code thing I'm not sure. Maybe I'll go get a cheap code reader just to be sure. Sorry Bounty. But I will still try the cleaning
 
Check the Zone, they should pull the codes for free.

Checking and resetting the codes always worked on our '98.
I've been wrong before, and I'm sure it won't be the last :wink:
 

This was the exact code that I was pulling and went through this with my 2000, most auto zones will pull the codes and reset for free. Unless you really ned a code reader I would not buy one. Mine ended up being the ingnition pick up on top of the oil pump drive gear(dealer only part costs about $30) Get the codes checked and see.
 
Nick, I disagree with you, at least as far as my own experience goes. I have always been able to clear the codes on my OBDII vehicles by disconnecting the POSITIVE terminal of the battery and letting it sit for about 10-15 minutes. I have also been able to clear them with the cheap harbour freight reader. I have checked codes with that reader after doing the battery trick and the harbour freight reader has always come up clear of codes after pulling the battery cable. Its been my understanding that the non-volitale memory is good only so long as the capacitors in the PCM can still store a charge. Once the battery is disconnected for a certain
amount of time the caps loose their charge and the memory goes away.
Maybe there are differences in OBDII circuits and memory in different vehicles. I'm not sure.
But to be sure, that $40.00 Harbour freight code reader is WELL worth the money. Just the hassle of going back and forth to Autozone to get the reader read for free when your trying to diagnose a problem pays for the reader in just gas money. The HF reader will read OBDII codes and more importantly automatically clear them after it goes through four cycle reads.
Also my '99TJ has a distributor, but also has the sentry key option which changed the on board reading procedure a bit. My'99 does not read codes with either the old procedure or the new one. The on-board reader was put back into TJ's at some later date I think 2001 02 2002. Anyone know?
 
Help please???????

Hi,

I have always thought that the codes cannot be cleared by simply removing power from the PCM. With that said, I was looking around on the OBD-II website at obdii.com, and found the following statements:

All cars built since January 1, 1996 have OBD-II systems. Manufacturers started incorporating OBD-II in various models as early as 1994. Some early OBD-II cars were not 100% compliant.
That’s why the MIL lamp won’t go out until the emissions problem has been repaired. Clearing the codes with your AutoTap scan tool or disconnecting the powertrain control module’s power supply won’t prevent the lamp from coming back on if the problem hasn’t been fixed.

Now, after reading that, maybe they are implying the codes get erased after power is removed? But regardless whether they do are not, it is important to note that the CEL will come back on and a the code will be re-thrown if you haven't solved the problem. :mrgreen:

-Nick :!:
 
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